4.5.2 Greatest hits from previous weeks

4.5.2.1 Assign the results from a Solve to variable(s)

http://mathematica.stackexchange.com/questions/6669/assign-the-results-from-a-solve-to-variables

 
I understand Mathematica can't assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables?
 

- asked by stevenvh (30 votes), answered by Artes (22 votes)

4.5.2.2 How to create a fascinating QR code like this?

http://mathematica.stackexchange.com/questions/120041/how-to-create-a-fascinating-qr-code-like-this

 
Check the facinating QRCode in my profile page here 
 
You can find that this QRCode is some sort of intriguing as the QRCode is a IMAGE ITSELF!!! 
 
So my question is, how to create such a QRCode  ...
 

- asked by Wjx (24 votes), answered by Wjx (19 votes)